The present invention relates to an ultraviolet-absorbing cover for a fluorescent lamp for cutting harmful ultraviolet rays generated from a lighting fixture, e.g., a fluorescent lamp, which causes luring flying insects, and relates to a lighting fixture equipped with the same.
Further, the present invention relates to a film to be covered on a windowpane for cutting harmful ultraviolet ray of sunrays and ultraviolet rays generated from a lighting fixture, e.g., a fluorescent lamp, which causes luring flying insects, and also relates to an ultraviolet-absorbing film for preventing discoloration of photographs and liquid crystal displays by cutting ultraviolet ray of sunrays and a fluorescent lamp.
For the purpose of interrupting ultraviolet ray of sunrays harmful to the human body and ultraviolet rays generated from fluorescent lamps which cause luring flying insects, paints containing ultraviolet absorbers and fluorescent lamps provided with heat-shrinkable films are on the market and are also suggested in JP-A-8-111208, JP-A-10-21714 and JP-A-11-106666 (the term xe2x80x9cJP-Axe2x80x9d as used herein means an xe2x80x9cunexamined published Japanese patent applicationxe2x80x9d). However, absorption edge of those ultraviolet absorbers is shorter than 380 nm for the purpose of suppressing a yellow tint, or they are capable of absorbing ultraviolet rays to a long wavelength of 410 nm but accompanied by a strong yellow tint, or dyes and pigments are added for adjusting the tone of color for suppressing a tint of yellow. That absorption edge is short means UV-cutting off performance is low, and in particular, three-wavelength type fluorescent lamps, which are expected to spread prevailingly, have not absorption at 380 nm or less, or little if any. Accordingly, since the performance of preventing flying insects of three-wavelength fluorescent lamps themselves is expected, there is no necessity for such contrivances. However, since there remains emission in the vicinity of 405 nm even with three-wavelength type fluorescent lamps, as is apparent from the phototaxis curve of insects (insects generally strongly react to the wavelengths near the ultraviolet region, and this wavelength dependence is graphed) as disclosed in JP-A-7-3189, it is necessary to interrupt the emission line in the vicinity of 405 nm for the purpose of effectively preventing flying insects, therefore it is desired to cut off the rays to 410 nm. The interruption of the rays to 410 nm is accompanied by a tint of yellow. A tint of yellow can be suppressed by the addition of dyes and pigments but this countermeasure results in the sacrifice of transmittance in the visible ray region.
Further, white lamination polyester films mixed with a fluorescent brightening agent as well as an ultraviolet absorber for the purpose of suppressing the yellowing degree due to ultraviolet irradiation which are excellent in light fastness, whitening property and adhesive property are suggested (JP-A-11-291432 and JP-A-11-26821), but the same drawbacks as above still remain unsolved.
Further, as an ultraviolet-cutting off cover for a fluorescent lamp, composition comprising a transparent resin containing a fluorescent brightening agent is suggested (JP-B-6-3682, (the term xe2x80x9cJP-Bxe2x80x9d as used herein means an xe2x80x9cexamined Japanese patent publicationxe2x80x9d)), but there is a problem in this technique that the fluorescent brightening agent is deteriorated and causes yellowing.
The present invention has been developed for solving the above-described problems.
Accordingly, an object of the present invention is to provide an exchangeable fluorescent lamp cover, which does not generate a yellow tint even by cutting the rays up to 410 nm longer than 380 nm by the addition of a fluorescent brightening agent emitting blue fluorescence which is a complementary color to yellow, which cover is highly transparent and having longer light fastness than the duration of a fluorescent lamp.
Other objects of the present invention is to provide a high transparent film to be covered on a windowpane which generates no yellow tint even by cutting the rays longer than 405 nm, in particular, the rays up to 410 nm longer than 380 nm by the addition of a fluorescent brightening agent emitting blue fluorescence which is a complementary color to yellow, and to provide a film for preventing discoloration of photographs and liquid crystal displays by cutting ultraviolet rays of sunrays and from a fluorescent lamp.
The objects of the present invention to provide an ultraviolet-cutting off cover for a fluorescent lamp comprising a thermoplastic resin containing a fluorescent brightening agent and a lighting fixture equipped with the same have been accomplished by the following means.
(1) A fluorescent lamp cover which comprises a transparent resin containing a fluorescent brightening agent so as to cut off 90% or more of the rays of 410 nm or less, wherein the fluorescent brightening agent is represented by the following formula (I): 
wherein R1 and R4 each independently represents a hydrogen atom, an alkyl group or an alkoxyl group; R2 and R3 each independently represents an alkyl group; and [A] represents a substituted aryl or substituted ethenyl group.
(2) The fluorescent lamp cover as described in the above item (1), wherein the compound represented by formula (I) is a compound represented by the following formula (II): 
wherein R5 and R7 have the same meaning as R2; R6 and R8 have the same meaning as R3; and n represents an integer of 1 or 2.
(3) The fluorescent lamp cover as described in the above item (1) or (2), wherein the transparent resin is a copolymer of from 1/99 mass % to 99/1 mass % of methyl methacrylate/styrene.
(4) A lighting fixture which comprises a broadband emission type or three-wavelength emission type fluorescent lamp covered with the cover as described in the above item (1), (2) or (3) so as to cut off the rays of 410 nm or less.
Further objects of the present invention to provide an ultraviolet ray-cutting off film containing a fluorescent brightening agent to be covered on a windowpane, and a film for preventing discoloration of photographs by cutting ultraviolet rays of sunrays and from a fluorescent lamp have been accomplished by the following means.
(5) An ultraviolet-absorbing film containing a fluorescent brightening agent and having a transmittance of the rays of 410 nm or less of 90% or less, wherein the fluorescent brightening agent is represented by the following formula (I): 
wherein R1 and R4 each independently represents a hydrogen atom, an alkyl group or an alkoxyl group; R2 and R3 each independently represents an alkyl group; and [A] represents a substituted aryl or substituted ethenyl group.
(6) The ultraviolet-absorbing film as described in the above item (5), wherein an ultraviolet absorber is further contained.
(7) The ultraviolet-absorbing film as described in the above item (5) or (6), which comprises a transparent support, an adhesive layer and a mold releasing paper.